Suriya who is famous for doing stunts without body doubles risked his life by jumping from a running train which is 90+ feet high.
The duration of movie is 164 mins. Product of the digits1x6x4 gives a 24. Also the story at the beginning of the movie happens on 13-01-1990 sum of the digits give again a 24. Not a coincidence
In an interview with The Hindu, Suriya told that recording of one more track was completed by September 2015. According to lyricist Madhan Karky, for the track "Naan Un", Rahman had composed a tune and wanted him to write something. He came up with the lines - "Naan Un Azhaginile Deivam Unarugiren". Rahman usually reads something for inspiration before composing the tunes and for this particular situation of composing the track, he had picked up a random page from a book and the lines he read there were: "In your beauty I see the manifestation of God" which translates back to "Naan Un Azhaginile Deivam Unarugiren". Karky noted this co-incidence on composing the track
This is the second tamil movie to feature time travelling, after Indru Netru Nallai.
Suriya appearing as an old man in this film, for which the make up takes about 5hr to complete